Question

URGENT..................
NO SPAMMING
GIVE REASON

Answer 1

Answer is Na+ .because in periodic table left to right radius get small. and positive ion have small size than parent atom

Answer 2

Na=11
Na+=10
Mg=12
Mg2+ =10
Al=13
Al3+=10
Cl= 17

Now

In Options (1)-(3) All Have same no: of electrons...But Different number of protons..
and Hence Different Nuclear charge...
And In case of Aluminium Its Nuclear charge is Very great to hold 10electrons (also it has attained Octet;more stability). and Hence its size decreases...

Same is the case for Sodium and Magnesium...
But In Ionic state Size of Al3+ < Mg2+<Na+

And Now along a Periodic table The size Decreases...
And But Cl has 17electrons And 17protons... And it is ready to accept 1more electron... Hence Out of the given 4 Cl Has the biggest size Since all Other are in Ionic state.

Hence Al3+ Has The smallest size ...

Hope it Helps...
Regards,
Leukonov.